JPS63224106A - Non-reducing dielectric ceramic composition - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] <Industrial Application Field> This invention is applicable to
Even if fired at temperatures below 360°C, it will not be reduced.
The absolute value of the temperature coefficient of capacitance is as small as 11000 pp/'C or less, the dielectric constant is 200 or more, and the dielectric loss is 0.
2% or less, and the specific resistance at 20℃ is 1×1012
The present invention relates to a non-reducible dielectric ceramic composition having a value larger than Ω1.

<Conventional technology and its problems> @! In the general manufacturing method for Ill ceramic capacitors, a conductive metal powder paste is printed and applied as internal electrodes onto a pre-fired ceramic sheet called a green sheet, which is wrapped using a method such as the doctor blade method.
A process is used in which a plurality of these sheets are alternately stacked, pressed together, and then fired.

It is known that conventional dielectric ceramic materials are reduced and converted into semiconductors when fired under neutral or low reducing oxygen partial pressures.

Therefore, the internal electrode metal of a multilayer capacitor that is fired at the same time as the dielectric ceramic should be a metal that does not melt at the sintering temperature of the dielectric ceramic and that does not oxidize during firing under high oxygen partial pressure that does not convert the ceramic into a semiconductor. Therefore, it is necessary to use expensive negative metals such as platinum or palladium, which has been an obstacle to miniaturization, large capacity, and cost reduction.

Based on the above, it has been desired to change the internal electrodes from expensive metals to inexpensive base metals in order to make multilayer ceramic capacitors smaller and more capacitive at low cost. In order to use N, it must have a high specific resistance that does not become a semiconductor even when fired at temperatures below 1360°C in a neutral or reducing atmosphere with a low oxygen partial pressure in which N is not oxidized or melted, and has a high enough resistivity as a dielectric for capacitors. There is a need for a ceramic dielectric material with excellent dielectric properties.

<Purpose of the invention> This invention uses N in the internal electrodes of a multilayer ceramic capacitor.
In order to make it possible to use inexpensive base metals such as Misaki, Fe, Cr, or their alloys, and to supply inexpensive small-sized multilayer ceramic capacitors, i! II
It does not undergo reduction even when fired at temperatures below 1360°C in a neutral or reducing atmosphere with low I partial pressure, the absolute value of the temperature coefficient of capacitance is as small as 1000 ppl/'C or less, and the dielectric constant is low. 200 or more, a dielectric loss of 0.2% or less, and a resistivity at 20° C. of more than 1×10 12 ΩC#.

Means for Solving the Problems> This invention has been made to solve the above problems, and its gist is that the composition formula (S71-
x Ca x ) n (T, 1-y Zry)
In a dielectric ceramic composition whose main component is a substance represented by Og, xly and m in the above formula have a molar ratio of 0.30≦x≦0.50, 0.03≦y≦0.20, respectively.
In the range of 0.95≦m≦1.08, and when the produced component is 100 parts by weight, 1 is converted to hot as a subcomponent. 0.1
0 to 4.00 heavy parts, and -O 0.01 to 1.00
The present invention provides a non-reducible dielectric ceramic composition characterized by containing a width portion.

<Reason for limiting the composition range> Compositional formula of the present invention (Sr 1-X Ca x ) ll
In the dielectric ceramic composition represented by (T & 1-y Zr,)03, the molar ratio of xly and m in the above formula is 0.30≦x≦0.50.0.03≦y≦0.20. 0
．． The reason for limiting 95≦m≦1.08 will be explained.

Setting the coefficient X in the range of 0.30≦x≦0.50 is 0
．． If it is smaller than 30 or larger than 0.50, the firing temperature will exceed 1360°C and the absolute value of the temperature coefficient of capacitance will be larger than 1000 pp11/'C, which is not preferable.

The relationship between e & y is 0.03 ≦y≦0.20. If the range is smaller than 0.03, the dielectric loss (tan δ) is 0.
．． 2%, and the specific resistance at 25° C. and 85° C. is lower than 1×10120α, which is undesirable.
When it is larger than 0.20, the firing temperature exceeds 1360℃ and the absolute value of the temperature coefficient of capacitance is 1000ppl/'
This is because it becomes larger than C, which is not preferable.

Furthermore, regarding the coefficient m, when the value is smaller than 0.95, the specific resistance at 25℃ and 85℃ is 1×1012Ωc.
When it becomes lower than JI and tan δ becomes thicker than 0.2%, which is undesirable, and when it is larger than 1.08,
The firing temperature becomes higher than 1,360°C, and the absolute value of the temperature coefficient of capacitance becomes larger than 11,000 pp/'C, which is not preferable.

Next, regarding the reason for limiting the range of the amount of subcomponents added, when the main component is lifted by 100 parts, if the amount of llnOt added is less than 0.01 parts by weight, the firing temperature will be 1360°C.
and tan δ is greater than 0.2%, and 25
℃ and 85℃, which is undesirable, and when the amount exceeds 2600 parts by weight, the absolute value of the temperature coefficient of capacitance is 1000 pp11/
' C and tan δ is larger than 0.2%, and the resistivity at 25°C and 85°C is also 1×
It is undesirable because it becomes lower than 1012Ωart.

Regarding the amount of SiOt added, if it is less than 0.10 parts by mass, the firing temperature will exceed 1,360°C and the absolute value of the temperature coefficient of capacitance will become larger than 11,000 ppr/'C, which is undesirable. When the number is more than 00, the dielectric constant is less than 200 and tan δ is 0.2%.
It gets bigger and I don't like it.

If the amount of 10 added is less than 0.011 peak, the specific resistance at 85°C will be lower than 1 x 1012ΩCJI, and 1,
00! If the number is larger than the I-hung portion, the absolute value of the temperature coefficient of capacitance becomes larger than 1000 pp11/'C, which is not preferable.

<Example> Hereinafter, this invention will be explained in detail with reference to Examples.

Industrial Sr Co 3 , Ca Co as starting materials
3, Zr Ot, Tb0e, rs+ot, 5
Using LOt, 10, the composition formula (Sr 1- xCa
) (TLl-yZry)Os+11nOt+5LO
e+t%O, and the mixtures were blended to approximately the blending ratio shown in Table 1.

Next, these raw materials were wet mixed in a ball mill, pulverized, evaporated to dryness, and calcined at 1150° C. for 2 hours in a natural atmosphere.

Next, 5 parts by weight of a vinyl acetate binder was added as a binding material to the calcined raw materials, and wet-mixed using a ball mill.
Further, through the steps of evaporation drying and sizing, the obtained powder raw material was heated to a pressure of 2.5 tons/- to a diameter of 1 oss and a thickness of 1.
It was molded into a 2-inch disk shape.

Next, this disc was placed in an alumina box sprinkled with zirconia powder, and the vinyl acetate binder was burned at 500°C in a natural atmosphere for 2 hours, resulting in a volume ratio of 82/
In a reducing gas atmosphere of N2 = 3/100,
It was baked at 1240-1360°C for 2 hours.

In-1 alloy was applied to both sides of the sintered 11B, and the dielectric constant (ε) and dielectric loss (tan δ) were adjusted to IK)-1z
, I Vrns, measured at 20°C.

Note that the temperature coefficient of capacitance is based on the capacitance at 20° C., and is calculated from the following equation from this and the capacitance at 85° C.

Electrostatic capacitance failure = munitions + o' (rr1f
I/QQ+ 1. ! ;-B Also, the specific resistance (ρ) is 50 at 20℃ and 85℃
It was determined from the current value that flows when a 21m voltage of 0V is applied. The results are shown in Table 2.

Note that the sample F4 fragrance marked with this mark in the table is outside the scope of the claims of this invention.

Table 1 <Effects of the Invention> From the above table, the non-reducing dielectric ceramic composition of the present invention is sintered at 1360°C or less in a reducing atmosphere, and the absolute value of the temperature coefficient of capacitance with respect to temperature is 11000 pp/ "C.
The dielectric constant is 200 or more and the dielectric loss is 0.
2% or less, and the specific resistance at 20℃ is 1×1012
It was confirmed that characteristics of Ωa or higher were obtained.

By using such a dielectric ceramic composition as a material for MA ceramic capacitors, it is possible to use base metals such as NL, Fe, and Cr, which are cheaper than conventional expensive pseudo metals, as internal electrodes. Therefore, it is possible to eliminate the increase in electrode cost due to the increase in the capacity of Vi layer ceramic capacitors, and it is possible to supply a multilayer ceramic capacitor with a low 111 rating.

In addition, in the examples, a reducing atmosphere consisting of N2-82 was used as the firing atmosphere, but Ar, Co, CO2, h
It goes without saying that atmospheric gases such as a, N2, and a mixture thereof may also be used.

Claims (1)

[Claims] Compositional formula (Sr_1_-_xCa_x)_m(Ti_1
In a dielectric ceramic composition whose main component is a substance represented by ____yZr_y)O_3, x, y and m in the above formula
are in the following molar ratios: 0.30≦x≦0.50, 0.03≦y≦0.20, 0.95≦m≦1.08, and when the main component is 100 parts by weight,
Mn as a subcomponent is converted to MnO_2 and is 0.01 to 2.
．． A non-reducible dielectric ceramic composition characterized by containing 0.00 parts by weight, 0.10 to 4.00 parts by weight of SiO_2, and 0.01 to 1.00 parts by weight of MgO.